<!DOCTYPE html>
<html lang="zh-CN">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        .btn-group {
            width: 600px;
            height: 600px;
            margin: 100px auto;
        }

        .pink {
            background-color: pink;
            color: white;
            box-shadow: 0 0 10px black;
            transition: all 1s;
            transform: scale(2);
        }

        button {
            margin-left: 50px;
        }

    </style>
</head>
<body>
<div class="btn-group">
    <button class="pink">按钮1</button>
    <button>按钮2</button>
    <button>按钮3</button>
    <button>按钮4</button>
</div>
<script>
    let btn = document.querySelectorAll('button');
    for (let i = 0; i < btn.length; i++) {
        btn[i].addEventListener('click', function () {
            document.querySelector('.pink').className = '';
            this.className = 'pink';
        });
    }
</script>

</body>
</html>